Carl Sagan

Carl Sagan

Overview
Carl Edward Sagan (ˈseɪɡən; November 9, 1934 – December 20, 1996) was an American astronomer, astrophysicist
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...

, cosmologist
Cosmology
Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order...

, author, science popularizer
Popular science
Popular science, sometimes called literature of science, is interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is broad-ranging, often written by scientists as well as journalists, and is presented in many...

 and science communicator
Science communication
Science communication generally refers to public media aiming to talk about science with non-scientists. This often involves professional scientists but has evolved into a professional field in its own right...

 in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books. He advocated scientifically skeptical inquiry and the scientific method, pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI
SETI
The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...

).

Sagan is known for his popular science
Popular science
Popular science, sometimes called literature of science, is interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is broad-ranging, often written by scientists as well as journalists, and is presented in many...

 books and for the award-winning 1980 television series Cosmos: A Personal Voyage
Cosmos: A Personal Voyage
Cosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles and Gregory Andorfer, and directed by the producers, David...

, which he narrated and co-wrote.
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Unanswered Questions
Quotations

We have designed our civilization based on science and technology and at the same time arranged things so that almost no one understands anything at all about science and technology. This is a clear prescription for disaster.

Interview with Anne Kalosh, 1995

I try not to think with my gut. If I'm serious about understanding the world, thinking with anything besides my brain, as tempting as that might be, is likely to get me into trouble.

...that kind of skeptical questioning, don't accept what authority tells you -attitude of science- is also nearly identical to the attitude of mind necessary for a functioning democracy. Science and democracy have very consonant values and approaches, and I don't think you can have one without the other.

Talk of the Nation, 3 May 1996

Who is more humble? The scientist who looks at the universe with an open mind and accepts whatever the universe has to teach us, or somebody who says everything in this book must be considered the literal truth and never mind the fallibility of all the human beings involved?

Interview with Charlie Rose, 1996

In science it often happens that scientists say, "You know that's a really good argument; my position is mistaken," and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.

Keynote address at CSICOP conference, 1987

I am convinced that there are genuine and valid levels of perception available with cannabis (and probably with other drugs) which are, through the defects of our society and our educational system, un-available to us without such drugs.

published in Dr. Lester Grinspoon's Marihuana Reconsidered (1971)
Encyclopedia
Carl Edward Sagan (ˈseɪɡən; November 9, 1934 – December 20, 1996) was an American astronomer, astrophysicist
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...

, cosmologist
Cosmology
Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order...

, author, science popularizer
Popular science
Popular science, sometimes called literature of science, is interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is broad-ranging, often written by scientists as well as journalists, and is presented in many...

 and science communicator
Science communication
Science communication generally refers to public media aiming to talk about science with non-scientists. This often involves professional scientists but has evolved into a professional field in its own right...

 in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books. He advocated scientifically skeptical inquiry and the scientific method, pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI
SETI
The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...

).

Sagan is known for his popular science
Popular science
Popular science, sometimes called literature of science, is interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is broad-ranging, often written by scientists as well as journalists, and is presented in many...

 books and for the award-winning 1980 television series Cosmos: A Personal Voyage
Cosmos: A Personal Voyage
Cosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles and Gregory Andorfer, and directed by the producers, David...

, which he narrated and co-wrote. The book Cosmos
Cosmos (book)
Cosmos is a popular science book by astronomer and Pulitzer Prize-winning author Carl Sagan. Its 13 illustrated chapters, corresponding to the 13 episodes of the Cosmos TV series on which the book was based, explore the mutual development of science and civilization...

 was published to accompany the series. Sagan wrote the novel Contact, the basis for a 1997 film of the same name.

Early life


Carl Sagan was born in Brooklyn
Brooklyn
Brooklyn is the most populous of New York City's five boroughs, with nearly 2.6 million residents, and the second-largest in area. Since 1896, Brooklyn has had the same boundaries as Kings County, which is now the most populous county in New York State and the second-most densely populated...

, New York, to a Ukrainian Jewish
History of the Jews in Ukraine
Jewish communities have existed in the territory of Ukraine from the time of Kievan Rus' and developed many of the most distinctive modern Jewish theological and cultural traditions. While at times they flourished, at other times they faced periods of persecution and antisemitic discriminatory...

 family. His father, Sam Sagan, was an immigrant garment worker from Kamenets-Podolsk, Ukraine; his mother, Rachel Molly Gruber, a housewife. Carl was named in honor of Rachel's biological mother, Chaiya Clara, in Sagan's words, "the mother she never knew." Sagan graduated from Rahway High School
Rahway High School
Rahway High School is a four-year public high school that serves students in ninth through twelfth grades from Rahway, in Union County, New Jersey, United States, operating as part of the Rahway Public Schools. The high school's present location was built in 1941...

 in Rahway, New Jersey
Rahway, New Jersey
Rahway is a city in southern Union County, New Jersey, United States. It is part of the New York metropolitan area, being 15 miles southwest of Manhattan and five miles west of Staten Island...

, in 1951.

He had a sister, Carol, and the family lived in a modest apartment near the Atlantic Ocean, in Bensonhurst, a Brooklyn neighborhood. According to Sagan, they were Reform
Reform Judaism
Reform Judaism refers to various beliefs, practices and organizations associated with the Reform Jewish movement in North America, the United Kingdom and elsewhere. In general, it maintains that Judaism and Jewish traditions should be modernized and should be compatible with participation in the...

 Jews, the most liberal of the three main Jewish groups. Both Sagan and his sister agree that their father was not especially religious, but that their mother "definitely believed in God, and was active in the temple ... and served only Kosher meat." During the height of the Depression
Great Depression
The Great Depression was a severe worldwide economic depression in the decade preceding World War II. The timing of the Great Depression varied across nations, but in most countries it started in about 1929 and lasted until the late 1930s or early 1940s...

, his father had to accept a job as a theater usher.

According to biographer Keay Davidson, Sagan's "inner war" was a result of his close relations with both his parents, who were in many ways "opposites." Sagan traced his later analytical urges to his mother, a woman who had known "extreme poverty as a child," and had grown up almost homeless in New York City during World War I and the 1920s. She had her own intellectual ambitions as a young woman, but they were blocked by social restrictions, because of her poverty, her being a woman and wife, and her Jewish ethnicity. Davidson notes that she therefore "worshiped her only son, Carl. He would fulfill her unfulfilled dreams."

However, his "sense of wonder" came from his father, who was a "quiet and soft-hearted escapee from the Czar." In his free time, he gave apples to the poor, or helped soothe labor-management tensions within New York's "tumultuous" garment industry. Although he was "awed" by Carl's "brilliance, his boyish chatter about stars and dinosaurs," he took his son's inquisitiveness in stride, as part of his growing up. In his later years as a writer and scientist, Sagan would often draw on his childhood memories to illustrate scientific points, as he did in his book, Shadows of Forgotten Ancestors. Sagan describes his parents' influence on his later thinking:
My parents were not scientists. They knew almost nothing about science. But in introducing me simultaneously to skepticism and to wonder, they taught me the two uneasily cohabiting modes of thought that are central to the scientific method.

1939 World's Fair


Sagan recalls that one of his best experiences was when he was four or five years old, his parents took him to the 1939 New York World's Fair
1939 New York World's Fair
The 1939–40 New York World's Fair, which covered the of Flushing Meadows-Corona Park , was the second largest American world's fair of all time, exceeded only by St. Louis's Louisiana Purchase Exposition of 1904. Many countries around the world participated in it, and over 44 million people...

. The exhibits became a turning point in his life. He later recalled the moving map of the "America of Tomorrow" exhibit: "It showed beautiful highways and cloverleaves and little General Motors cars all carrying people to skyscrapers, buildings with lovely spires, flying buttresses—and it looked great!" At other exhibits, he remembered how a flashlight that shined on a photoelectric cell created a cracking sound, and how the sound from a tuning fork became a wave on an oscilloscope. He also witnessed the future media technology that would replace radio: television. Sagan wrote:
Plainly, the world held wonders of a kind I had never guessed. How could a tone become a picture and light become a noise?


He also saw one of the Fair's most publicized events, the burial of a time capsule at Flushing Meadows
Flushing Meadows
Flushing Meadows is an American short film by Larry Jordan, with director Joseph Cornell. The film is 8 minutes long, in color, 16mm, and silent....

, which contained mementos of the 1930s to be recovered by Earth's descendants in a future millennium. "The time capsule thrilled Carl," writes Davidson. As an adult, Sagan and his colleagues created similar time capsules, but ones that would be sent out into the galaxy. These were the Pioneer plaque
Pioneer plaque
The Pioneer plaques are a pair of gold-anodized aluminium plaques which were placed on board the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft, featuring a pictorial message, in case either Pioneer 10 or 11 are intercepted by extraterrestrial life...

 and the Voyager Golden Record
Voyager Golden Record
The Voyager Golden Records are phonograph records which were included aboard both Voyager spacecraft, which were launched in 1977. They contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form, or for...

records, all of which were spinoffs of Sagan's memories of the World Fair.

World War II


During World War II, Sagan's family worried about the fate of their European relatives. Sagan, however, was generally unaware of the details of the ongoing war. He writes, "Sure, we had relatives who were caught up in the Holocaust. Hitler was not a popular fellow in our household ... But on the other hand, I was fairly insulated from the horrors of the war." His sister, Carol, said that their mother "above all wanted to protect Carl ... She had an extraordinarily difficult time dealing with World War II and the Holocaust." Sagan's book, The Demon-Haunted World (1996), included his memories of this conflicted period in his life, where his family dealt with the realities of the war in Europe, but tried to prevent it from undermining his optimistic spirit.

Inquisitiveness about nature


Soon after entering elementary school
Elementary school
An elementary school or primary school is an institution where children receive the first stage of compulsory education known as elementary or primary education. Elementary school is the preferred term in some countries, particularly those in North America, where the terms grade school and grammar...

, he began to express a strong inquisitiveness about nature. Sagan recalled taking his first trips to the public library
Public library
A public library is a library that is accessible by the public and is generally funded from public sources and operated by civil servants. There are five fundamental characteristics shared by public libraries...

 alone, at the age of five, when his mother got him a library card. He wanted to learn what stars were, since none of his friends or their parents could give him a clear answer:
I went to the librarian and asked for a book about stars ... And the answer was stunning. It was that the Sun was a star but really close. The stars were suns, but so far away they were just little points of light ... The scale of the universe suddenly opened up to me. It was a kind of religious experience. There was a magnificence to it, a grandeur, a scale which has never left me. Never ever left me.


About the time he was six or seven, he and a close friend took trips to the American Museum of Natural History
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...

 in New York City. While there, they went to the Hayden Planetarium
Hayden Planetarium
The Hayden Planetarium is a public planetarium, part of the Rose Center for Earth and Space of the American Museum of Natural History in New York City, currently directed by astrophysicist Dr. Neil deGrasse Tyson....

 and walked around the museum's exhibits of space objects, such as meteorites, and displays of dinosaurs and animals in natural settings. Sagan writes about those visits:
I was transfixed by the dioramas—lifelike representations of animals and their habitats all over the world. Penguin
Penguin
Penguins are a group of aquatic, flightless birds living almost exclusively in the southern hemisphere, especially in Antarctica. Highly adapted for life in the water, penguins have countershaded dark and white plumage, and their wings have become flippers...

s on the dimly lit Antarctic ice; ... a family of gorilla
Gorilla
Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...

s, the male beating his chest, ... an American grizzly bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...

 standing on his hind legs, ten or twelve feet tall, and staring me right in the eye.


His parents helped nurture his growing interest in science by buying him chemistry sets and reading materials. His interest in space, however, was his primary focus, especially after reading science fiction stories by writers such as Edgar Rice Burroughs
Edgar Rice Burroughs
Edgar Rice Burroughs was an American author, best known for his creation of the jungle hero Tarzan and the heroic Mars adventurer John Carter, although he produced works in many genres.-Biography:...

, which stirred his imagination about life on other planets, such as Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. According to biographer Ray Spangenburg, these early years as Sagan tried to understand the mysteries of the planets, became a "driving force in his life, a continual spark to his intellect, and a quest that would never be forgotten."

Education and scientific career


He attended the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...

, where he participated in the Ryerson Astronomical Society, received a bachelor of arts
Bachelor of Arts
A Bachelor of Arts , from the Latin artium baccalaureus, is a bachelor's degree awarded for an undergraduate course or program in either the liberal arts, the sciences, or both...

 with general and special honors in 1954, a bachelor of science
Bachelor of Science
A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years .-Australia:In Australia, the BSc is a 3 year degree, offered from 1st year on...

 in 1955, and a master of science
Master of Science
A Master of Science is a postgraduate academic master's degree awarded by universities in many countries. The degree is typically studied for in the sciences including the social sciences.-Brazil, Argentina and Uruguay:...

 in physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 in 1956 before earning a PhD in astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 and astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...

 in 1960. During his time as an undergraduate
Undergraduate education
Undergraduate education is an education level taken prior to gaining a first degree . Hence, in many subjects in many educational systems, undergraduate education is post-secondary education up to the level of a bachelor's degree, such as in the United States, where a university entry level is...

, Sagan worked in the laboratory of the geneticist
Geneticist
A geneticist is a biologist who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a researcher or lecturer. Some geneticists perform experiments and analyze data to interpret the inheritance of skills. A geneticist is also a Consultant or...

 H. J. Muller
Hermann Joseph Muller
Hermann Joseph Muller was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation as well as his outspoken political beliefs...

. From 1960 to 1962 Sagan was a Miller Fellow
Miller Research Fellows
The Miller Fellow program is the central program of the Adolph C. and Mary Sprague Miller Institute for Basic Research in Science on the University of California Berkeley campus, which constitutes the support of Research Fellows - a group of the world’s most brilliant young scientists...

 at the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...

. From 1962 to 1968, he worked at the Smithsonian Astrophysical Observatory
Smithsonian Astrophysical Observatory
The Smithsonian Astrophysical Observatory is a research institute of the Smithsonian Institution headquartered in Cambridge, Massachusetts, where it is joined with the Harvard College Observatory to form the Harvard-Smithsonian Center for Astrophysics .-History:The SAO was founded in 1890 by...

 in Cambridge, Massachusetts
Cambridge, Massachusetts
Cambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, an important center of the Puritan theology embraced by the town's founders. Cambridge is home to two of the world's most prominent...

.

Sagan lectured and did research at Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...

 until 1968, when he moved to Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

 in Ithaca, New York
Ithaca, New York
The city of Ithaca, is a city in upstate New York and the county seat of Tompkins County, as well as the largest community in the Ithaca-Tompkins County metropolitan area...

. He became a full Professor
Professor
A professor is a scholarly teacher; the precise meaning of the term varies by country. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences; a teacher of high rank...

 at Cornell in 1971, and he directed the Laboratory for Planetary Studies
Planetary science
Planetary science is the scientific study of planets , moons, and planetary systems, in particular those of the Solar System and the processes that form them. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation,...

 there. From 1972 to 1981, Sagan was the Associate Director of the Center for Radio Physics and Space Research at Cornell.

Sagan was associated with the American space program from its inception. From the 1950s onward, he worked as an advisor to NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

, where one of his duties included briefing the Apollo astronaut
Astronaut
An astronaut or cosmonaut is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft....

s before their flights to the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. Sagan contributed to many of the robotic spacecraft
Robotic spacecraft
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...

 missions that explored the solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...

, arranging experiments on many of the expeditions. He conceived the idea of adding an unalterable and universal message on spacecraft destined to leave the solar system that could potentially be understood by any extraterrestrial intelligence that might find it. Sagan assembled the first physical message that was sent into space
Outer space
Outer space is the void that exists between celestial bodies, including the Earth. It is not completely empty, but consists of a hard vacuum containing a low density of particles: predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, and neutrinos....

: a gold-
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

anodized plaque
Pioneer plaque
The Pioneer plaques are a pair of gold-anodized aluminium plaques which were placed on board the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft, featuring a pictorial message, in case either Pioneer 10 or 11 are intercepted by extraterrestrial life...

, attached to the space probe Pioneer 10
Pioneer 10
Pioneer 10 is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System. The project was managed by the NASA Ames Research Center and the contract for the construction of the...

, launched in 1972. Pioneer 11
Pioneer 11
Pioneer 11 is a 259-kilogram robotic space probe launched by NASA on April 6, 1973 to study the asteroid belt, the environment around Jupiter and Saturn, solar wind, cosmic rays, and eventually the far reaches of the solar system and heliosphere...

, also carrying another copy of the plaque, was launched the following year. He continued to refine his designs; the most elaborate message he helped to develop and assemble was the Voyager Golden Record
Voyager Golden Record
The Voyager Golden Records are phonograph records which were included aboard both Voyager spacecraft, which were launched in 1977. They contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form, or for...

 that was sent out with the Voyager
Voyager program
The Voyager program is a U.S program that launched two unmanned space missions, scientific probes Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable planetary alignment of the late 1970s...

 space probes in 1977. Sagan often challenged the decisions to fund the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...

 and Space Station
Space station
A space station is a spacecraft capable of supporting a crew which is designed to remain in space for an extended period of time, and to which other spacecraft can dock. A space station is distinguished from other spacecraft used for human spaceflight by its lack of major propulsion or landing...

 at the expense of further robotic missions.

Sagan taught a course on critical thinking
Critical thinking
Critical thinking is the process or method of thinking that questions assumptions. It is a way of deciding whether a claim is true, false, or sometimes true and sometimes false, or partly true and partly false. The origins of critical thinking can be traced in Western thought to the Socratic...

 at Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

 until he died in 1996 from pneumonia, a few months after finding that he was in remission of myelodysplastic syndrome
Myelodysplastic syndrome
The myelodysplastic syndromes are a diverse collection of hematological medical conditions that involve ineffective production of the myeloid class of blood cells....

.

Scientific achievements


Sagan's contributions were central to the discovery of the high surface temperatures of the planet Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...

. In the early 1960s no one knew for certain the basic conditions of that planet's surface, and Sagan listed the possibilities in a report later depicted for popularization in a Time-Life
Time-Life
Time–Life is a creator and direct marketer of books, music, video/DVD, and multimedia products. Its products are sold throughout North America, Europe, Australia, and Asia through television, print, retail, the Internet, telemarketing, and direct sales....

 book, Planets. His own view was that Venus was dry and very hot as opposed to the balmy paradise others had imagined. He had investigated radio emissions from Venus and concluded that there was a surface temperature of 500 °C. As a visiting scientist to NASA's Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

, he contributed to the first Mariner
Mariner program
The Mariner program was a program conducted by the American space agency NASA that launched a series of robotic interplanetary probes designed to investigate Mars, Venus and Mercury from 1963 to 1973...

 missions to Venus, working on the design and management of the project. Mariner 2
Mariner 2
Mariner 2 , an American space probe to Venus, was the first space probe to conduct a successful planetary encounter . The first successful spacecraft in the NASA Mariner program, it was a simplified version of the Block I spacecraft of the Ranger program and an exact copy of Mariner 1...

 confirmed his conclusions on the surface conditions of Venus in 1962.

Sagan was among the first to hypothesize that Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...

's moon Titan
Titan (moon)
Titan , or Saturn VI, is the largest moon of Saturn, the only natural satellite known to have a dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found....

 might possess oceans of liquid compounds on its surface and that Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

's moon Europa
Europa (moon)
Europa Slightly smaller than Earth's Moon, Europa is primarily made of silicate rock and probably has an iron core. It has a tenuous atmosphere composed primarily of oxygen. Its surface is composed of ice and is one of the smoothest in the Solar System. This surface is striated by cracks and...

 might possess subsurface oceans of water. This would make Europa potentially habitable for life. Europa's subsurface ocean of water was later indirectly confirmed by the spacecraft Galileo. Sagan also helped solve the mystery of the reddish haze seen on Titan, revealing that it is composed of complex organic molecules constantly raining down onto the moon's surface.

He further contributed insights regarding the atmospheres of Venus and Jupiter as well as seasonal changes on Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Sagan established that the atmosphere of Venus is extremely hot and dense with pressures increasing steadily all the way down to the surface. He also perceived global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...

 as a growing, man-made danger and likened it to the natural development of Venus into a hot, life-hostile planet through a kind of runaway greenhouse effect
Runaway greenhouse effect
A runaway greenhouse effect is not a clearly defined term, but is understood to mean an event analogous to that which is believed to have happened in the early history of Venus, where positive feedback increased the strength of its greenhouse effect until its oceans boiled away...

. Sagan and his Cornell colleague Edwin Ernest Salpeter
Edwin Ernest Salpeter
Edwin Ernest Salpeter FRS was an Austrian-Australian-American astrophysicist. Born to a Jewish family, he emigrated from Austria to Australia while in his teens to escape the Nazis. He attended Sydney University, where he obtained his bachelor's degree in 1944 and his master's degree in 1945...

 speculated about life in Jupiter's clouds, given the planet's dense atmospheric composition rich in organic molecules. He studied the observed color variations on Mars' surface and concluded that they were not seasonal or vegetational changes as most believed but shifts in surface dust caused by windstorms.

Sagan is best known, however, for his research on the possibilities of extraterrestrial life, including experimental demonstration of the production of amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

s from basic chemicals by radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

.

He is also the 1994 recipient of the Public Welfare Medal
Public Welfare Medal
The Public Welfare Medal is awarded by the U.S. National Academy of Sciences "in recognition of distinguished contributions in the application of science to the public welfare." It is the most prestigious honor conferred by the Academy...

, the highest award of the National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...

 for "distinguished contributions in the application of science to the public welfare." He was denied membership in the Academy, reportedly because his media activities made him unpopular with many other scientists.

Scientific advocacy



Sagan's ability to convey his ideas allowed many people to better understand the cosmos—simultaneously emphasizing the value and worthiness of the human race, and the relative insignificance of the Earth in comparison to the universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...

. He delivered the 1977 series of Royal Institution Christmas Lectures
Royal Institution Christmas Lectures
The Royal Institution Christmas Lectures are a series of lectures on a single topic, which have been held at the Royal Institution in London each year since 1825. The lectures present scientific subjects to a general audience, including young people, in an informative and entertaining manner....

 in London. He hosted and, with Ann Druyan
Ann Druyan
Ann Druyan is an American author and producer specializing in productions about cosmology and popular science. She made substantial contributions to the PBS documentary series, Cosmos, and was the wife of late scientist and educator, Carl Sagan.-Film career:Along with Carl Sagan and Steven Soter,...

, co-wrote and co-produced the highly popular thirteen-part PBS television series Cosmos: A Personal Voyage
Cosmos: A Personal Voyage
Cosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles and Gregory Andorfer, and directed by the producers, David...

modeled on Jacob Bronowski
Jacob Bronowski
Jacob Bronowski was a Polish-Jewish British mathematician, biologist, historian of science, theatre author, poet and inventor...

's The Ascent of Man
The Ascent of Man
The Ascent of Man is a thirteen-part documentary television series produced by the BBC and Time-Life Films first transmitted in 1973, written and presented by Jacob Bronowski...

.

Sagan was a proponent of the search for extraterrestrial life. He urged the scientific community to listen with radio telescope
Radio telescope
A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...

s for signals from potential intelligent extraterrestrial life-forms. Sagan was so persuasive that by 1982 he was able to get a petition advocating SETI
SETI
The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...

 published in the journal Science and signed by 70 scientists including seven Nobel Prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...

 winners. This was a tremendous increase in the respectability of this controversial field. Sagan also helped Dr. Frank Drake
Frank Drake
Frank Donald Drake PhD is an American astronomer and astrophysicist. He is most notable as one of the pioneers in the search for extraterrestrial intelligence, including the founding of SETI, mounting the first observational attempts at detecting extraterrestrial communications in 1961 in Project...

 write the Arecibo message
Arecibo message
The Arecibo message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope on 16 November 1974. It was aimed at the globular star cluster M13 some 25,000 light years away because M13 was a large and close...

, a radio message beamed into space from the Arecibo radio telescope on November 16, 1974, aimed at informing potential extraterrestrials about Earth.

Sagan was chief technology officer of the professional planetary research journal Icarus
Icarus (journal)
Icarus is a premier scientific journal dedicated to the field of planetary science. It is published under the auspices of the American Astronomical Society's Division for Planetary Sciences . The longtime publisher was Academic Press, which is now part of Elsevier...

for twelve years. He co-founded the Planetary Society
Planetary Society
The Planetary Society is a large, publicly supported, non-government and non-profit organization that has many research projects related to astronomy...

, the largest space-interest group in the world, with over 100,000 members in more than 149 countries, and was a member of the SETI Institute
SETI Institute
The SETI Institute is a not-for-profit organization whose mission is to “explore, understand and explain the origin, nature and prevalence of life in the universe”. SETI stands for the "search for extraterrestrial intelligence". One program is the use of both radio and optical telescopes to search...

 Board of Trustees. Sagan served as Chairman of the Division for Planetary Science of the American Astronomical Society
American Astronomical Society
The American Astronomical Society is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC...

, as President of the Planetology Section of the American Geophysical Union
American Geophysical Union
The American Geophysical Union is a nonprofit organization of geophysicists, consisting of over 50,000 members from over 135 countries. AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international field of geophysics...

, and as Chairman of the Astronomy Section of the American Association for the Advancement of Science
American Association for the Advancement of Science
The American Association for the Advancement of Science is an international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the...

.

At the height of the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

, Sagan became involved in public awareness efforts for the effects of nuclear war
Nuclear warfare
Nuclear warfare, or atomic warfare, is a military conflict or political strategy in which nuclear weaponry is detonated on an opponent. Compared to conventional warfare, nuclear warfare can be vastly more destructive in range and extent of damage...

 when a mathematical climate model suggested that a substantial nuclear exchange could upset the delicate balance of life on Earth. He was one of five authors—the "S" of the "TTAPS" report as the research paper came to be known. He eventually co-authored the scientific paper hypothesizing a global nuclear winter
Nuclear winter
Nuclear winter is a predicted climatic effect of nuclear war. It has been theorized that severely cold weather and reduced sunlight for a period of months or even years could be caused by detonating large numbers of nuclear weapons, especially over flammable targets such as cities, where large...

 following nuclear war. He also co-authored the book A Path Where No Man Thought: Nuclear Winter and the End of the Arms Race, a comprehensive examination of the phenomenon of nuclear winter.

Cosmos covered a wide range of scientific subjects including the origin of life and a perspective of our place in the universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...

. The series was first broadcast by the Public Broadcasting Service
Public Broadcasting Service
The Public Broadcasting Service is an American non-profit public broadcasting television network with 354 member TV stations in the United States which hold collective ownership. Its headquarters is in Arlington, Virginia....

 in 1980, winning an Emmy
Emmy Award
An Emmy Award, often referred to simply as the Emmy, is a television production award, similar in nature to the Peabody Awards but more focused on entertainment, and is considered the television equivalent to the Academy Awards and the Grammy Awards .A majority of Emmys are presented in various...

 and a Peabody Award
Peabody Award
The George Foster Peabody Awards recognize distinguished and meritorious public service by radio and television stations, networks, producing organizations and individuals. In 1939, the National Association of Broadcasters formed a committee to recognize outstanding achievement in radio broadcasting...

. It has been broadcast in more than 60 countries and seen by over 500 million people, making it the most widely watched PBS
Public Broadcasting Service
The Public Broadcasting Service is an American non-profit public broadcasting television network with 354 member TV stations in the United States which hold collective ownership. Its headquarters is in Arlington, Virginia....

 program in history. In addition, Time magazine ran a cover story about Sagan soon after the show broadcast, referring to him as "creator, chief writer and host-narrator of the new public television series Cosmos, [and] takes the controls of his fantasy spaceship."

Sagan also wrote books to popularize science which reflected and expanded upon some of the themes of A Personal Voyage, and became the best-selling science book ever published in English; The Dragons of Eden: Speculations on the Evolution of Human Intelligence
The Dragons of Eden
The Dragons of Eden: Speculations on the Evolution of Human Intelligence is a Pulitzer Prize winning 1977 book by Carl Sagan. In it, he combines the fields of anthropology, evolutionary biology, psychology, and computer science to give a perspective of how human intelligence evolved.One of the main...

, which won a Pulitzer Prize
Pulitzer Prize
The Pulitzer Prize is a U.S. award for achievements in newspaper and online journalism, literature and musical composition. It was established by American publisher Joseph Pulitzer and is administered by Columbia University in New York City...

; and Broca's Brain: Reflections on the Romance of Science
Broca's Brain: Reflections on the Romance of Science
Broca's Brain: Reflections on the Romance of Science is a 1979 book by astrophysicist Carl Sagan. Its chapters were originally articles published between 1974 and 1979 in various magazines, including Atlantic Monthly, New Republic, Physics Today, Playboy and Scientific American...

. Sagan also wrote the best-selling science fiction novel Contact
Contact (novel)
Contact is a science fiction novel written by Carl Sagan and published in 1985. It deals with the theme of contact between humanity and a more technologically advanced, extraterrestrial life form. It ranked No. 7 on the 1985 U.S. bestseller list....

 in 1985, based on a film treatment
Film treatment
A film treatment is a piece of prose, typically the step between scene cards and the first draft of a screenplay for a motion picture, television program, or radio play. It is generally longer and more detailed than an outline , and it may include details of directorial style that an outline omits...

 he wrote with his wife in 1979, but he did not live to see the book's 1997 motion picture adaptation
Contact (film)
Contact is a 1997 American science fiction drama film adapted from the Carl Sagan novel of the same name and directed by Robert Zemeckis. Both Sagan and wife Ann Druyan wrote the story outline for the film adaptation of Contact....

, which starred Jodie Foster
Jodie Foster
Alicia Christian "Jodie" Foster is an American actress, film director, producer as well as a former child actress....

 and won the 1998 Hugo Award
Hugo Award
The Hugo Awards are given annually for the best science fiction or fantasy works and achievements of the previous year. The award is named after Hugo Gernsback, the founder of the pioneering science fiction magazine Amazing Stories, and was officially named the Science Fiction Achievement Awards...

 for Best Dramatic Adaption.

He wrote a sequel to Cosmos, Pale Blue Dot: A Vision of the Human Future in Space
Pale Blue Dot (book)
Pale Blue Dot: A Vision of the Human Future in Space is a non-fiction book by Carl Sagan. It is the sequel to Cosmos: A Personal Voyage and was inspired by the "Pale Blue Dot" photograph, for which Sagan provides a sobering description...

, which was selected as a notable book of 1995 by The New York Times
The New York Times
The New York Times is an American daily newspaper founded and continuously published in New York City since 1851. The New York Times has won 106 Pulitzer Prizes, the most of any news organization...

. He appeared on PBS' Charlie Rose
Charlie Rose
Charles Peete "Charlie" Rose, Jr. is an American television talk show host and journalist. Since 1991 he has hosted Charlie Rose, an interview show distributed nationally by PBS since 1993...

 program in January 1995. Sagan also wrote an introduction for the bestselling book by Stephen Hawking
Stephen Hawking
Stephen William Hawking, CH, CBE, FRS, FRSA is an English theoretical physicist and cosmologist, whose scientific books and public appearances have made him an academic celebrity...

, A Brief History of Time
A Brief History of Time
A Brief History of Time is a popular science book written by renown physicist Stephen Hawking and first published by the Bantam Dell Publishing Group in 1988. It became a best-seller and has sold more than 10 million copies...

. Sagan was also known for his popularization of science, his efforts to increase scientific understanding among the general public, and his positions in favor of scientific skepticism
Scientific skepticism
Scientific skepticism is the practice of questioning the veracity of claims lacking empirical evidence or reproducibility, as part of a methodological norm pursuing "the extension of certified knowledge". For example, Robert K...

 and against pseudoscience
Pseudoscience
Pseudoscience is a claim, belief, or practice which is presented as scientific, but which does not adhere to a valid scientific method, lacks supporting evidence or plausibility, cannot be reliably tested, or otherwise lacks scientific status...

, such as his debunking
Debunker
A debunker is an individual who attempts to discredit and contradict claims as being false, exaggerated or pretentious. The term is closely associated with skeptical investigation of, or in some cases irrational resistance to, controversial topics such as U.F.O.s, claimed paranormal phenomena,...

 of the Betty and Barney Hill abduction
Betty and Barney Hill abduction
Betty and Barney Hill were an American couple who claimed to have been abducted by extraterrestrials in a rural portion of New Hampshire on September 19–20, 1961....

. To mark the tenth anniversary of Sagan's death, David Morrison, a former student of Sagan, recalled "Sagan's immense contributions to planetary research, the public understanding of science, and the skeptical movement" in Skeptical Inquirer
Skeptical Inquirer
The Skeptical Inquirer is a bimonthly American magazine published by the Committee for Skeptical Inquiry with the subtitle: The magazine for science and reason....

.

Sagan hypothesized in January 1991 that enough smoke from the 1991 Kuwaiti oil fires
Kuwaiti oil fires
The Kuwaiti oil fires were caused by Iraqi military forces setting fire to 700 oil wells as part of a scorched earth policy while retreating from Kuwait in 1991 after invading the country but being driven out by Coalition military forces...

 "might get so high as to disrupt agriculture in much of South Asia ..." He later conceded in The Demon-Haunted World that this prediction did not turn out to be correct: "it was pitch black at noon and temperatures dropped 4°–6°C over the Persian Gulf, but not much smoke reached stratospheric altitudes and Asia was spared." A 2007 study noted that modern computer models have been applied to the Kuwait oil fires, finding that individual smoke plumes are not able to loft smoke into the stratosphere, but that smoke from fires covering a large area, like some forest fires or the burning of cities that would be expected to follow a nuclear strike, would loft significant amounts of smoke into the stratosphere.

In his later years Sagan advocated the creation of an organized search for near Earth objects that might impact the Earth. When others suggested creating large nuclear bombs that could be used to alter the orbit of a NEO that was predicted to hit the Earth, Sagan proposed the Deflection Dilemma: If we create the ability to deflect an asteroid away from the Earth, then we also create the ability to deflect an asteroid towards the Earth—providing an evil power with a true doomsday bomb.

Billions and billions


From Cosmos and his frequent appearances on The Tonight Show Starring Johnny Carson
The Tonight Show Starring Johnny Carson
The Tonight Show Starring Johnny Carson is a talk show hosted by Johnny Carson under the Tonight Show franchise from 1962 to 1992. It originally aired during late-night....

, Sagan became associated with the catchphrase "billions and billions". Sagan stated that he never actually used the phrase in the Cosmos series. The closest that he ever came was in the book Cosmos, where he talked of "billions upon billions":
However, his frequent use of the word billions, and distinctive delivery emphasizing the "b" (which he did intentionally, in place of more cumbersome alternatives such as "billions with a 'b'", in order to distinguish the word from "millions" in viewers' minds), made him a favorite target of comic performers, including Johnny Carson
Johnny Carson
John William "Johnny" Carson was an American television host and comedian, known as host of The Tonight Show Starring Johnny Carson for 30 years . Carson received six Emmy Awards including the Governor Award and a 1985 Peabody Award; he was inducted into the Television Academy Hall of Fame in 1987...

, Gary Kroeger
Gary Kroeger
Gary Kroeger is an American actor best known for his work on Saturday Night Live from 1982 to 1985.Born in Cedar Falls, Iowa, Kroeger attended Northern University High School and graduated from Northwestern University in 1981. He joined the cast of Saturday Night Live during Lorne Michaels' hiatus...

, Mike Myers, Bronson Pinchot
Bronson Pinchot
Bronson Alcott Pinchot is an American actor. He has appeared in several feature films, including Risky Business, Beverly Hills Cop , The First Wives Club, True Romance, Courage Under Fire and It's My Party...

, Penn Jillette
Penn Jillette
Penn Fraser Jillette is an American magician, comedian, illusionist, juggler, bassist and a best-selling author known for his work with fellow illusionist Teller in the team Penn & Teller, and advocacy of atheism, libertarian philosophy, free-market economics, and scientific skepticism.-Early...

, Harry Shearer
Harry Shearer
Harry Julius Shearer is an American actor, comedian, writer, voice artist, musician, author, radio host and director. He is known for his long-running role on The Simpsons, his work on Saturday Night Live, the comedy band Spinal Tap and his radio program Le Show...

, and others. Frank Zappa
Frank Zappa
Frank Vincent Zappa was an American composer, singer-songwriter, electric guitarist, record producer and film director. In a career spanning more than 30 years, Zappa wrote rock, jazz, orchestral and musique concrète works. He also directed feature-length films and music videos, and designed...

 satirized the line in the song "Be In My Video", noting as well "atomic light". Sagan took this all in good humor, and his final book was entitled Billions and Billions
Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium
Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium, published by Random House in 1997 , is the last book written by renowned American astronomer and science popularizer Carl Sagan before his death in 1996....

which opened with a tongue-in-cheek discussion of this catchphrase, observing that Carson himself was an amateur astronomer and that Carson's comic caricature often included real science.

The popular perception of his characterization of large cosmic quantities continued to be a sense of wonderment at the vastness of space and time, as in his phrase "The total number of stars in the Universe is larger than all the grains of sand on all the beaches of the planet Earth." However, this famous saying was widely misunderstood, as he was in fact referring to the world being at a "critical branch point in history" as in the following quote from Cosmos: A Personal Voyage
Cosmos: A Personal Voyage
Cosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles and Gregory Andorfer, and directed by the producers, David...

, Episode 8: "Journeys in Space and Time":
"Those worlds in space are as countless as all the grains of sand on all the beaches of the earth. Each of those worlds is as real as ours and every one of them is a succession of incidents, events, occurrences which influence its future. Countless worlds, numberless moments, an immensity of space and time. And our small planet at this moment, here we face a critical branch point in history: what we do with our world, right now, will propagate down through the centuries and powerfully affect the destiny of our descendants. It is well within our power to destroy our civilization and perhaps our species as well."

Sagan units


As a humorous tribute to him, a sagan has been defined as a unit of measurement equal to at least four billion, since the smallest number that may be described as billions and billions must be two billion plus two billion.

Social concerns


Sagan believed that the Drake equation
Drake equation
The Drake equation is an equation used to estimate the number of detectable extraterrestrial civilizations in the Milky Way galaxy. It is used in the fields of exobiology and the Search for ExtraTerrestrial Intelligence...

, on substitution of reasonable estimates, suggested that a large number of extraterrestrial civilizations would form, but that the lack of evidence of such civilizations highlighted by the Fermi paradox
Fermi paradox
The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations....

 suggests technological civilizations tend to self-destruct. This stimulated his interest in identifying and publicizing ways that humanity could destroy itself, with the hope of avoiding such a cataclysm
Doomsday event
A doomsday event is a specific, plausibly verifiable or hypothetical occurrence which has an exceptionally destructive effect on the human race...

 and eventually becoming a spacefaring
Spacefaring
To be spacefaring is to be capable of and active in the art of space travel or space transport, the operation of spacecraft or spaceplanes. It involves a knowledge of a variety of topics and development of specialised skills including : aeronautics; astronautics; programs to train astronauts; space...

 species. Sagan's deep concern regarding the potential destruction of human civilization in a nuclear holocaust
Nuclear holocaust
Nuclear holocaust refers to the possibility of the near complete annihilation of human civilization by nuclear warfare. Under such a scenario, all or most of the Earth is made uninhabitable by nuclear weapons in future world wars....

 was conveyed in a memorable cinematic sequence in the final episode of Cosmos
Cosmos: A Personal Voyage
Cosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles and Gregory Andorfer, and directed by the producers, David...

, called "Who Speaks for Earth?" Sagan had already resigned from the Air Force Scientific Advisory Board and voluntarily surrendered his top secret clearance in protest over the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

. Following his marriage to his third wife (novelist Ann Druyan
Ann Druyan
Ann Druyan is an American author and producer specializing in productions about cosmology and popular science. She made substantial contributions to the PBS documentary series, Cosmos, and was the wife of late scientist and educator, Carl Sagan.-Film career:Along with Carl Sagan and Steven Soter,...

) in June 1981, Sagan became more politically active—particularly in opposing escalation of the nuclear arms race
Nuclear arms race
The nuclear arms race was a competition for supremacy in nuclear warfare between the United States, the Soviet Union, and their respective allies during the Cold War...

 under President Ronald Reagan
Ronald Reagan
Ronald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....

.

In March 1983, Reagan announced the Strategic Defense Initiative
Strategic Defense Initiative
The Strategic Defense Initiative was proposed by U.S. President Ronald Reagan on March 23, 1983 to use ground and space-based systems to protect the United States from attack by strategic nuclear ballistic missiles. The initiative focused on strategic defense rather than the prior strategic...

—a multi-billion dollar project to develop a comprehensive defense
Missile defense
Missile defense is a system, weapon, or technology involved in the detection, tracking, interception and destruction of attacking missiles. Originally conceived as a defence against nuclear-armed Intercontinental ballistic missiles , its application has broadened to include shorter-ranged...

 against attack by nuclear missiles, which was quickly dubbed the "Star Wars" program. Sagan spoke out against the project, arguing that it was technically impossible to develop a system with the level of perfection required, and far more expensive to build than for an enemy to defeat through decoy
Decoy
A decoy is usually a person, device or event meant as a distraction, to conceal what an individual or a group might be looking for. Decoys have been used for centuries most notably in game hunting, but also in wartime and in the committing or resolving of crimes.-Duck decoy:The term duck decoy may...

s and other means—and that its construction would seriously destabilize the nuclear balance between the United States and the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

, making further progress toward nuclear disarmament
Nuclear disarmament
Nuclear disarmament refers to both the act of reducing or eliminating nuclear weapons and to the end state of a nuclear-free world, in which nuclear weapons are completely eliminated....

 impossible.

When Soviet leader Mikhail Gorbachev
Mikhail Gorbachev
Mikhail Sergeyevich Gorbachev is a former Soviet statesman, having served as General Secretary of the Communist Party of the Soviet Union from 1985 until 1991, and as the last head of state of the USSR, having served from 1988 until its dissolution in 1991...

 declared a unilateral moratorium on the testing of nuclear weapons
Nuclear testing
Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...

, which would begin on August 6, 1985—the 40th anniversary of the atomic bombing of Hiroshima
Atomic bombings of Hiroshima and Nagasaki
During the final stages of World War II in 1945, the United States conducted two atomic bombings against the cities of Hiroshima and Nagasaki in Japan, the first on August 6, 1945, and the second on August 9, 1945. These two events are the only use of nuclear weapons in war to date.For six months...

—the Reagan administration dismissed the dramatic move as nothing more than propaganda
Propaganda
Propaganda is a form of communication that is aimed at influencing the attitude of a community toward some cause or position so as to benefit oneself or one's group....

, and refused to follow suit. In response, American anti-nuclear
Anti-nuclear
The anti-nuclear movement is a social movement that opposes the use of nuclear technologies. Many direct action groups, environmental groups, and professional organisations have identified themselves with the movement at the local, national, and international level...

 and peace activists staged a series of protest actions at the Nevada Test Site
Nevada Test Site
The Nevada National Security Site , previously the Nevada Test Site , is a United States Department of Energy reservation located in southeastern Nye County, Nevada, about northwest of the city of Las Vegas...

, beginning on Easter Sunday in 1986 and continuing through 1987. Hundreds of people were arrested, including Sagan, who was arrested on two separate occasions as he climbed over a chain-link fence at the test site.

Personal life and beliefs


Sagan was married three times—in 1957, to biologist Lynn Margulis
Lynn Margulis
Lynn Margulis was an American biologist and University Professor in the Department of Geosciences at the University of Massachusetts Amherst. She is best known for her theory on the origin of eukaryotic organelles, and her contributions to the endosymbiotic theory, which is now generally accepted...

, mother of Dorion Sagan
Dorion Sagan
Dorion Sagan is an American science writer, essayist, and theorist. He has written and co-authored many books on culture, evolution, and the history and philosophy of science, most recently "The Sciences of Avatar: from Anthropology to Xenology" and "Death and Sex," which won first place at the...

 and Jeremy Sagan
Jeremy Sagan
Jeremy Sagan is an American computer programmer. He is the founder of Sagan Technology and author of Metro: an audio, MIDI and video sequencer for Apple Macintosh computers....

; in 1968, to artist Linda Salzman
Linda Salzman Sagan
Linda Salzman Sagan is an artist and writer, famed for creating the artwork for the plaque on the Pioneer spacecraft and for coproducing the Voyager Golden Record. She co-authored the book Murmurs of Earth with her ex-husband, astronomer Carl Sagan, whom she married on April 6, 1968; the marriage...

, mother of Nick Sagan
Nick Sagan
Nick Sagan is an American novelist and screenwriter. He is the author of the science fiction novels Idlewild, Edenborn, and Everfree, and his screen credits include episodes of Star Trek: The Next Generation and Star Trek: Voyager...

; and in 1981, to author Ann Druyan
Ann Druyan
Ann Druyan is an American author and producer specializing in productions about cosmology and popular science. She made substantial contributions to the PBS documentary series, Cosmos, and was the wife of late scientist and educator, Carl Sagan.-Film career:Along with Carl Sagan and Steven Soter,...

, mother of Alexandra Rachel (Sasha) Sagan and Samuel Democritus Sagan. His marriage to Druyan continued until his death in 1996.

Isaac Asimov
Isaac Asimov
Isaac Asimov was an American author and professor of biochemistry at Boston University, best known for his works of science fiction and for his popular science books. Asimov was one of the most prolific writers of all time, having written or edited more than 500 books and an estimated 90,000...

 described Sagan as one of only two people he ever met whose intellect surpassed his own. The other, he claimed, was the computer scientist
Computer science
Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...

 and artificial intelligence
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...

 expert Marvin Minsky
Marvin Minsky
Marvin Lee Minsky is an American cognitive scientist in the field of artificial intelligence , co-founder of Massachusetts Institute of Technology's AI laboratory, and author of several texts on AI and philosophy.-Biography:...

.

Sagan wrote frequently about religion and the relationship between religion and science, expressing his skepticism about the conventional conceptualization of God as a sapient being. For example:

Some people think God is an outsized, light-skinned male with a long white beard, sitting on a throne somewhere up there in the sky, busily tallying the fall of every sparrow. Others—for example Baruch Spinoza
Baruch Spinoza
Baruch de Spinoza and later Benedict de Spinoza was a Dutch Jewish philosopher. Revealing considerable scientific aptitude, the breadth and importance of Spinoza's work was not fully realized until years after his death...

 and Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

—considered God to be essentially the sum total of the physical laws which describe the universe. I do not know of any compelling evidence for anthropomorphic patriarchs controlling human destiny from some hidden celestial vantage point, but it would be madness to deny the existence of physical laws.


In another description of his view of God, Sagan emphatically writes:

The idea that God is an oversized white male with a flowing beard who sits in the sky and tallies the fall of every sparrow is ludicrous. But if by God one means the set of physical laws that govern the universe, then clearly there is such a God. This God is emotionally unsatisfying... it does not make much sense to pray to the law of gravity.


Despite his criticism of religion, Sagan denied that he was an atheist, saying "An atheist has to know a lot more than I know. An atheist is someone who knows there is no god. By some definitions atheism is very stupid." In reply to a question in 1996 about his religious beliefs, Sagan answered, "I'm agnostic." Sagan's views on religion have been interpreted as a form of pantheism
Pantheism
Pantheism is the view that the Universe and God are identical. Pantheists thus do not believe in a personal, anthropomorphic or creator god. The word derives from the Greek meaning "all" and the Greek meaning "God". As such, Pantheism denotes the idea that "God" is best seen as a process of...

 comparable to Einstein's belief in Spinoza's God. Sagan maintained that the idea of a creator of the universe was difficult to prove or disprove and that the only conceivable scientific discovery that could challenge it would be an infinitely old universe. According to his last wife, Ann Druyan, he was not a believer:

In 2006, Ann Druyan edited Sagan's 1985 Glasgow Gifford Lectures
Gifford Lectures
The Gifford Lectures were established by the will of Adam Lord Gifford . They were established to "promote and diffuse the study of Natural Theology in the widest sense of the term — in other words, the knowledge of God." The term natural theology as used by Gifford means theology supported...

 in Natural Theology
into a book, The Varieties of Scientific Experience: A Personal View of the Search for God, in which he elaborates on his views of divinity in the natural world
Nature
Nature, in the broadest sense, is equivalent to the natural world, physical world, or material world. "Nature" refers to the phenomena of the physical world, and also to life in general...

.

Sagan is also widely regarded as a freethinker or skeptic; one of his most famous quotations, in Cosmos, was, "Extraordinary claims require extraordinary evidence" (called the "Sagan Standard" by some). This was based on a nearly identical statement by fellow founder of the Committee for the Scientific Investigation of Claims of the Paranormal, Marcello Truzzi
Marcello Truzzi
Marcello Truzzi was a professor of sociology at New College of Florida and later at Eastern Michigan University, founding co-chairman of the Committee for the Scientific Investigation of Claims of the Paranormal , a founder of the Society for Scientific Exploration, and director for the Center for...

, "An extraordinary claim requires extraordinary proof." This idea originated with Pierre-Simon Laplace
Pierre-Simon Laplace
Pierre-Simon, marquis de Laplace was a French mathematician and astronomer whose work was pivotal to the development of mathematical astronomy and statistics. He summarized and extended the work of his predecessors in his five volume Mécanique Céleste...

 (1749–1827), a French mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....

 and astronomer who said, "The weight of evidence for an extraordinary claim must be proportioned to its strangeness."

Late in his life, Sagan's books elaborated on his skeptical, naturalistic
Naturalism (philosophy)
Naturalism commonly refers to the philosophical viewpoint that the natural universe and its natural laws and forces operate in the universe, and that nothing exists beyond the natural universe or, if it does, it does not affect the natural universe that we know...

 view of the world. In The Demon-Haunted World: Science as a Candle in the Dark, he presented tools for testing arguments and detecting fallacious or fraudulent ones, essentially advocating wide use of critical thinking and the scientific method
Scientific method
Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of...

. The compilation Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium
Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium
Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium, published by Random House in 1997 , is the last book written by renowned American astronomer and science popularizer Carl Sagan before his death in 1996....

, published in 1997 after Sagan's death, contains essays written by Sagan, such as his views on abortion
Abortion
Abortion is defined as the termination of pregnancy by the removal or expulsion from the uterus of a fetus or embryo prior to viability. An abortion can occur spontaneously, in which case it is usually called a miscarriage, or it can be purposely induced...

, and his widow Ann Druyan's account of his death as a skeptic
Skepticism
Skepticism has many definitions, but generally refers to any questioning attitude towards knowledge, facts, or opinions/beliefs stated as facts, or doubt regarding claims that are taken for granted elsewhere...

, agnostic
Agnosticism
Agnosticism is the view that the truth value of certain claims—especially claims about the existence or non-existence of any deity, but also other religious and metaphysical claims—is unknown or unknowable....

, and freethinker
Freethought
Freethought is a philosophical viewpoint that holds that opinions should be formed on the basis of science, logic, and reason, and should not be influenced by authority, tradition, or other dogmas...

.

Sagan warned against humans' tendency towards anthropocentrism
Anthropocentrism
Anthropocentrism describes the tendency for human beings to regard themselves as the central and most significant entities in the universe, or the assessment of reality through an exclusively human perspective....

. He was the faculty adviser for the Cornell Students for the Ethical Treatment of Animals. In the Cosmos chapter "Blues For a Red Planet", Sagan wrote, "If there is life on Mars, I believe we should do nothing with Mars. Mars then belongs to the Martians, even if the Martians are only microbes."

Sagan was a user and advocate of marijuana
Cannabis (drug)
Cannabis, also known as marijuana among many other names, refers to any number of preparations of the Cannabis plant intended for use as a psychoactive drug or for medicinal purposes. The English term marijuana comes from the Mexican Spanish word marihuana...

. Under the pseudonym "Mr. X", he contributed an essay about smoking cannabis to the 1971 book Marihuana Reconsidered. The essay explained that marijuana use had helped to inspire some of Sagan's works and enhance sensual and intellectual experiences. After Sagan's death, his friend Lester Grinspoon
Lester Grinspoon
Dr. Lester Grinspoon is Associate Professor Emeritus of Psychiatry at Harvard Medical School. Grinspoon was senior psychiatrist at the Massachusetts Mental Health Center in Boston for 40 years. Dr. Grinspoon is a fellow of the American Association for the Advancement of Science and the American...

 disclosed this information to Sagan's biographer, Keay Davidson. The publishing of the biography, Carl Sagan: A Life, in 1999 brought media attention to this aspect of Sagan's life. Not long after his death, widow Ann Druyan had gone on to preside over the board of directors of NORML, a foundation dedicated to reforming cannabis laws.

In 1994, engineers at Apple Computer
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...

 code-named the Power Macintosh 7100
Power Macintosh 7100
The Power Macintosh 7100 was a mid-range Apple Macintosh personal computer that was designed, manufactured and sold by Apple Computer from March 1994 to January 1996. The PowerMac 7100 was faster and more expandable than the Power Macintosh 6100, and was a part of the original Power Macintosh line...

 "Carl Sagan" in the hope that Apple would make "billions and billions" with the sale of the PowerMac 7100. The name was only used internally, but Sagan was concerned that it would become a product endorsement and sent Apple a cease and desist letter. Apple complied, but engineers retaliated by changing the internal codename to "BHA" for "Butt-Head Astronomer". Sagan then sued Apple for libel, a form of defamation, in federal court. The court granted Apple's motion to dismiss Sagan's claims and opined in dicta
Obiter dictum
Obiter dictum is Latin for a statement "said in passing". An obiter dictum is a remark or observation made by a judge that, although included in the body of the court's opinion, does not form a necessary part of the court's decision...

 that a reader aware of the context would understand Apple was "clearly attempting to retaliate in a humorous and satirical way", and that "It strains reason to conclude that Defendant was attempting to criticize Plaintiff's reputation or competency as an astronomer. One does not seriously attack the expertise of a scientist using the undefined phrase 'butt-head'." Sagan then sued for Apple's original use of his name and likeness, but again lost. Sagan appealed the ruling. In November 1995, an out of court settlement was reached and Apple's office of trademarks and patents released a conciliatory statement that "Apple has always had great respect for Dr. Sagan. It was never Apple's intention to cause Dr. Sagan or his family any embarrassment or concern."

Sagan briefly served as an adviser on Stanley Kubrick
Stanley Kubrick
Stanley Kubrick was an American film director, writer, producer, and photographer who lived in England during most of the last four decades of his career...

's film 2001: A Space Odyssey
2001: A Space Odyssey (film)
2001: A Space Odyssey is a 1968 epic science fiction film produced and directed by Stanley Kubrick, and co-written by Kubrick and Arthur C. Clarke, partially inspired by Clarke's short story The Sentinel...

. Sagan proposed that the film would suggest, rather than depict, extraterrestrial superintelligence.

Sagan and UFOs


Sagan had some interest in UFO
Unidentified flying object
A term originally coined by the military, an unidentified flying object is an unusual apparent anomaly in the sky that is not readily identifiable to the observer as any known object...

 reports from at least 1964 when he had several conversations on the subject with Jacques Vallee
Jacques Vallée
Jacques Fabrice Vallée is a venture capitalist, computer scientist, author, ufologist and former astronomer currently residing in San Francisco, California....

. Though quite skeptical of any extraordinary answer to the UFO question, Sagan thought scientists should study the phenomenon, at least because there was widespread public interest in UFO reports.

Stuart Appelle
Stuart Appelle
Dr. Stuart Appelle was a professor and writer, with an interest in topics dealing with anomalous perception, including hypnotic experience, and reports of unidentified flying objects and alien abduction.-Biography:...

 notes that Sagan "wrote frequently on what he perceived as the logic
Logic
In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...

al and empirical
Empiricism
Empiricism is a theory of knowledge that asserts that knowledge comes only or primarily via sensory experience. One of several views of epistemology, the study of human knowledge, along with rationalism, idealism and historicism, empiricism emphasizes the role of experience and evidence,...

 fallacies
Fallacy
In logic and rhetoric, a fallacy is usually an incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor , or take advantage of social relationships between people...

 regarding UFOs and the abduction experience
Abduction phenomenon
The terms alien abduction or abduction phenomenon describe "subjectively real memories of being taken secretly against one’s will by apparently nonhuman entities and subjected to complex physical and psychological procedures." People claiming to have been abducted are usually called "abductees" or...

. Sagan rejected an extraterrestrial explanation
Extraterrestrial hypothesis
The extraterrestrial hypothesis is the hypothesis that some unidentified flying objects are best explained as being extraterrestrial life or non-human aliens from other planets occupying physical spacecraft visiting Earth.-Etymology:...

 for the phenomenon but felt there were both empirical and pedagogical
Pedagogy
Pedagogy is the study of being a teacher or the process of teaching. The term generally refers to strategies of instruction, or a style of instruction....

 benefits for examining UFO reports and that the subject was, therefore, a legitimate topic of study."

In 1966, Sagan was a member of the Ad Hoc Committee to Review Project Blue Book
Project Blue Book
Project Blue Book was one of a series of systematic studies of unidentified flying objects conducted by the United States Air Force. Started in 1952, it was the second revival of such a study...

, the U.S. Air Force's UFO investigation project. The committee concluded Blue Book had been lacking as a scientific study, and recommended a university-based project to give the UFO phenomenon closer scientific scrutiny. The result was the Condon Committee
Condon Committee
The Condon Committee was the informal name of the University of Colorado UFO Project, a group funded by the United States Air Force from 1966 to 1968 at the University of Colorado to study unidentified flying objects under the direction of physicist Edward Condon...

 (1966–1968), led by physicist Edward Condon
Edward Condon
Edward Uhler Condon was a distinguished American nuclear physicist, a pioneer in quantum mechanics, and a participant in the development of radar and nuclear weapons during World War II.-Early life and career:...

, and in their final report they formally concluded that UFOs, regardless of what any of them actually were, did not behave in a manner consistent with a threat to national security.

Ron Westrum
Ron Westrum
-Education:Born in Chicago in 1945, Westrum earned a B.A. in Social Relations in 1966 from Harvard University and a Ph.D. in Sociology in 1972 from the University of Chicago.-Expertise:...

 writes that "The high point of Sagan's treatment of the UFO question was the AAAS
American Association for the Advancement of Science
The American Association for the Advancement of Science is an international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the...

's symposium in 1969. A wide range of educated opinions on the subject were offered by participants, including not only proponents such as James McDonald
James E. McDonald
James Edward McDonald was an American physicist. He is best known for his research regarding UFOs. McDonald was senior physicist at the Institute for Atmospheric Physics and professor in the Department of Meteorology, University of Arizona, Tucson.McDonald campaigned vigorously in support of...

 and J. Allen Hynek
J. Allen Hynek
Dr. Josef Allen Hynek was a United States astronomer, professor, and ufologist. He is perhaps best remembered for his UFO research. Hynek acted as scientific adviser to UFO studies undertaken by the U.S. Air Force under three consecutive names: Project Sign , Project Grudge , and Project Blue Book...

 but also skeptics like astronomers William Hartmann
William Kenneth Hartmann
William K. Hartmann is a noted planetary scientist, author, and writer. He was the first to convince the scientific mainstream that the Earth had once been hit by a planet sized body , creating both the moon and the Earth's 23° tilt....

 and Donald Menzel. The roster of speakers was balanced, and it is to Sagan's credit that this event was presented in spite of pressure from Edward Condon
Edward Condon
Edward Uhler Condon was a distinguished American nuclear physicist, a pioneer in quantum mechanics, and a participant in the development of radar and nuclear weapons during World War II.-Early life and career:...

". With physicist Thornton Page, Sagan edited the lectures and discussions given at the symposium; these were published in 1972 as UFOs: A Scientific Debate. Some of Sagan's many books examine UFOs (as did one episode of Cosmos) and he claimed a religious undercurrent to the phenomenon.

Sagan again revealed his views on interstellar travel in his 1980 Cosmos series. In one of his last written works, Sagan argued that the chances of extraterrestrial spacecraft visiting Earth are vanishingly small. However, Sagan did think it plausible that Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

 concerns contributed to governments misleading their citizens about UFOs, and that "some UFO reports and analyses, and perhaps voluminous files, have been made inaccessible to the public which pays the bills ... It's time for the files to be declassified and made generally available." He cautioned against jumping to conclusions about suppressed UFO data and stressed that there was no strong evidence that aliens were visiting the Earth either in the past or present.

Death



After a long and difficult fight with myelodysplasia
Myelodysplastic syndrome
The myelodysplastic syndromes are a diverse collection of hematological medical conditions that involve ineffective production of the myeloid class of blood cells....

, which included three bone marrow transplants, Sagan died of pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...

 at the age of 62 at the Fred Hutchinson Cancer Research Center
Fred Hutchinson Cancer Research Center
The Fred Hutchinson Cancer Research Center, is one of the world’s leading cancer research institutes...

 in Seattle, Washington, on December 20, 1996. He was buried at Lakeview Cemetery in Ithaca, New York
Ithaca, New York
The city of Ithaca, is a city in upstate New York and the county seat of Tompkins County, as well as the largest community in the Ithaca-Tompkins County metropolitan area...

.

Posthumous recognition


The 1997 movie Contact
Contact (film)
Contact is a 1997 American science fiction drama film adapted from the Carl Sagan novel of the same name and directed by Robert Zemeckis. Both Sagan and wife Ann Druyan wrote the story outline for the film adaptation of Contact....

, based on Sagan's novel of the same name
Contact (novel)
Contact is a science fiction novel written by Carl Sagan and published in 1985. It deals with the theme of contact between humanity and a more technologically advanced, extraterrestrial life form. It ranked No. 7 on the 1985 U.S. bestseller list....

 and finished after his death, ends with the dedication "For Carl".

In 1997, the Sagan Planet Walk was opened in Ithaca New York. It is a walking scale model of the solar system, extending 1.2 km from the center of The Commons in downtown Ithaca, NY, to the Sciencenter, a hands-on museum. The exhibition was created in memory of Carl Sagan, who was an Ithaca resident and Cornell Professor. Professor Sagan had been a founding member of the museum's advisory board.

The landing site of the unmanned Mars Pathfinder
Mars Pathfinder
Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 spacecraft was renamed the Carl Sagan Memorial Station on July 5, 1997. Asteroid 2709 Sagan
2709 Sagan
2709 Sagan is a small main belt asteroid, which was discovered by Edward L. G. Bowell in 1982. It is named after the late astronomer Carl Sagan.Sagan is an S-type asteroid, meaning that it is stony in composition....

 is named in his honor.

Sagan's son, Nick Sagan
Nick Sagan
Nick Sagan is an American novelist and screenwriter. He is the author of the science fiction novels Idlewild, Edenborn, and Everfree, and his screen credits include episodes of Star Trek: The Next Generation and Star Trek: Voyager...

, wrote several episodes in the Star Trek
Star Trek
Star Trek is an American science fiction entertainment franchise created by Gene Roddenberry. The core of Star Trek is its six television series: The Original Series, The Animated Series, The Next Generation, Deep Space Nine, Voyager, and Enterprise...

franchise. In an episode of Star Trek: Enterprise
Star Trek: Enterprise
Star Trek: Enterprise is a science fiction television series. It follows the adventures of humanity's first warp 5 starship, the Enterprise, ten years before the United Federation of Planets shown in previous Star Trek series was formed.Enterprise premiered on September 26, 2001...

entitled "Terra Prime", a quick shot is shown of the relic rover Sojourner
Mars Pathfinder
Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

, part of the Mars Pathfinder mission, placed by a historical marker at Carl Sagan Memorial Station
Mars Pathfinder
Mars Pathfinder was an American spacecraft that landed a base station with roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight wheeled robotic rover named Sojourner.Launched on December 4, 1996 by NASA aboard a Delta II booster a...

 on the Martian surface. The marker displays a quote from Sagan: "Whatever the reason you're on Mars, I'm glad you're there, and I wish I was with you." Sagan's student Steve Squyres
Steve Squyres
Steven W. Squyres is the Goldwin Smith Professor of Astronomy at Cornell University in Ithaca, New York. His research area is in planetary sciences, with a focus on large solid bodies in the solar system such as the terrestrial planets and the moons of the Jovian planets. Squyres is principal...

 led the team that landed the Spirit Rover
Spirit rover
Spirit, MER-A , is a robotic rover on Mars, active from 2004 to 2010. It was one of two rovers of NASA's ongoing Mars Exploration Rover Mission. It landed successfully on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity , landed on the other side of the planet...

 and Opportunity Rover
Opportunity rover
Opportunity, MER-B , is a robotic rover on the planet Mars, active since 2004. It is the remaining rover in NASA's ongoing Mars Exploration Rover Mission...

 successfully on Mars in 2004.

On November 9, 2001, on what would have been Sagan's 67th birthday, the NASA Ames Research Center
NASA Ames Research Center
The Ames Research Center , is one of the United States of America's National Aeronautics and Space Administration 10 major field centers.The centre is located in Moffett Field in California's Silicon Valley, near the high-tech companies, entrepreneurial ventures, universities, and other...

 dedicated the site for the Carl Sagan Center for the Study of Life in the Cosmos. "Carl was an incredible visionary, and now his legacy can be preserved and advanced by a 21st century research and education laboratory committed to enhancing our understanding of life in the universe and furthering the cause of space exploration for all time", said NASA Administrator Daniel Goldin
Daniel Goldin
Daniel Saul Goldin served as the 9th and longest-tenured Administrator of NASA from April 1, 1992, to November 17, 2001. He was appointed by President George H. W. Bush and also served under President William Jefferson Clinton and George W...

. Ann Druyan was at the Center as it opened its doors on October 22, 2006.

Sagan has at least three awards named in his honor:
  • The Carl Sagan Memorial Award
    Carl Sagan Memorial Award
    The Carl Sagan Memorial Award is an award presented jointly by the American Astronautical Society and The Planetary Society to an individual or group "who has demonstrated leadership in research or policies advancing exploration of the Cosmos." The annual award, first presented in 1997, was created...

     presented jointly since 1997 by the American Astronomical Society (AAS)
    American Astronomical Society
    The American Astronomical Society is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC...

     and the Planetary Society
    Planetary Society
    The Planetary Society is a large, publicly supported, non-government and non-profit organization that has many research projects related to astronomy...

    ,
  • The Carl Sagan Medal
    Carl Sagan Medal
    The Carl Sagan Medal for Excellence in Public Communication in Planetary Science was established by the Division for Planetary Sciences of the American Astronomical Society to recognize and honor outstanding communication by an active planetary scientist to the general public...

     for Excellence in Public Communication in Planetary Science presented since 1998 by the American Astronomical Society's Division for Planetary Sciences
    Division for Planetary Sciences
    The Division for Planetary Sciences is a division within the American Astronomical Society devoted to solar system research. It was founded in 1968. The first organizing committee members were: Edward Anders, L. Branscomb, J. W. Chamberlain, R. Goody, J. S. Hall, A. Kliore, M. B. Elroy, Tobias...

     (AAS/DPS) for outstanding communication by an active planetary scientist to the general public—Carl Sagan was one of the original organizing committee members of the DPS, and
  • The Carl Sagan Award for Public Understanding of Science
    Carl Sagan Award for Public Understanding of Science
    The Carl Sagan Award for Public Understanding of Science is an award presented by the Council of Scientific Society Presidents to individuals who have become “concurrently accomplished as researchers and/or educators, and as widely recognized magnifiers of the public's understanding of science.”...

     presented by the Council of Scientific Society Presidents (CSSP)—Sagan himself was the first recipient of the CSSP award in 1993.

In 2006, the Carl Sagan Medal was awarded to astrobiologist and author David Grinspoon
David Grinspoon
David H. Grinspoon is an American astrobiologist. He is the current curator of Astrobiology at the Denver Museum of Nature and Science. He has published numerous works, such as Lonely Planets: The Natural Philosophy of Alien Life, which won the 2004 PEN literary award for nonfiction.Currently, he...

, the son of Sagan's friend Lester Grinspoon
Lester Grinspoon
Dr. Lester Grinspoon is Associate Professor Emeritus of Psychiatry at Harvard Medical School. Grinspoon was senior psychiatrist at the Massachusetts Mental Health Center in Boston for 40 years. Dr. Grinspoon is a fellow of the American Association for the Advancement of Science and the American...

.

On December 20, 2006, the tenth anniversary of Sagan's death, a blogger, Joel Schlosberg, organized a Carl Sagan "blog-a-thon" to commemorate Sagan's death, and the idea was supported by Nick Sagan. Many members of the blogging community participated.

August 2007 the Independent Investigative Group IIG awarded Sagan posthumously a Lifetime Achievement Award. This honor has also been awarded to Harry Houdini
Harry Houdini
Harry Houdini was a Hungarian-born American magician and escapologist, stunt performer, actor and film producer noted for his sensational escape acts...

 and James Randi
James Randi
James Randi is a Canadian-American stage magician and scientific skeptic best known as a challenger of paranormal claims and pseudoscience. Randi is the founder of the James Randi Educational Foundation...

.

Awards and honors


  • Annual Award for Television Excellence—1981—The Ohio State University
    Ohio State University
    The Ohio State University, commonly referred to as Ohio State, is a public research university located in Columbus, Ohio. It was originally founded in 1870 as a land-grant university and is currently the third largest university campus in the United States...

    —PBS series Cosmos
    Cosmos: A Personal Voyage
    Cosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles and Gregory Andorfer, and directed by the producers, David...

  • Apollo Achievement Award—National Aeronautics and Space Administration
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

  • NASA Distinguished Public Service Medal
    NASA Distinguished Public Service Medal
    The NASA Distinguished Public Service Medal is an award similar to the NASA Distinguished Service Medal, but awarded to non-government personnel. This is the highest honor NASA awards to anyone who was not a government employee when the service was performed....

    —National Aeronautics and Space Administration (twice)
  • Emmy—Outstanding Individual Achievement—1981—PBS series Cosmos
  • Emmy—Outstanding Informational Series—1981—PBS series Cosmos
  • Exceptional Scientific Achievement Medal
    NASA Exceptional Achievement Medal
    The NASA Exceptional Achievement Medal is an award of the National Aeronautics and Space Administration that was established in 1991. The medal is awarded to both civilian members of NASA and military astronauts....

    —National Aeronautics and Space Administration
  • Helen Caldicott
    Helen Caldicott
    Helen Mary Caldicott is an Australian physician, author, and anti-nuclear advocate who has founded several associations dedicated to opposing the use of nuclear power, depleted uranium munitions, nuclear weapons, nuclear weapons proliferation, war and military action in general. She hosts a...

     Leadership Award—Women's Action for Nuclear Disarmament
  • Hugo Award
    Hugo Award
    The Hugo Awards are given annually for the best science fiction or fantasy works and achievements of the previous year. The award is named after Hugo Gernsback, the founder of the pioneering science fiction magazine Amazing Stories, and was officially named the Science Fiction Achievement Awards...

    —1981—Cosmos
  • Humanist of the Year—1981—Awarded by the American Humanist Association
    American Humanist Association
    The American Humanist Association is an educational organization in the United States that advances Humanism. "Humanism is a progressive philosophy of life that, without theism and other supernatural beliefs, affirms our ability and responsibility to lead ethical lives of personal fulfillment that...

  • In Praise of Reason Award—1987—Committee for the Scientific Investigation of Claims of the Paranormal
    Committee for the Scientific Investigation of Claims of the Paranormal
    The Committee for Skeptical Inquiry , formerly known as the Committee for the Scientific Investigation of Claims of the Paranormal , is a program within the U.S...

  • Isaac Asimov Award
    Isaac Asimov Award
    Three distinct awards have been named for writer, chemist, and humanist Isaac Asimov.* The Isaac Asimov Award for Undergraduate Excellence in Science Fiction and Fantasy Short Story Writing is an annual award open to undergraduate college students and given to the author of the best science fiction...

    —1994—Committee for the Scientific Investigation of Claims of the Paranormal
    Committee for the Scientific Investigation of Claims of the Paranormal
    The Committee for Skeptical Inquiry , formerly known as the Committee for the Scientific Investigation of Claims of the Paranormal , is a program within the U.S...

  • John F. Kennedy
    John F. Kennedy
    John Fitzgerald "Jack" Kennedy , often referred to by his initials JFK, was the 35th President of the United States, serving from 1961 until his assassination in 1963....

     Astronautics
    Astronautics
    Astronautics, and related astronautical engineering, is the theory and practice of navigation beyond the Earth's atmosphere. In other words, it is the science and technology of space flight....

     Award—American Astronautical Society
    American Astronautical Society
    Formed in 1954, the American Astronautical Society is an independent scientific and technical group in the United States dedicated to the advancement of space science and exploration. AAS supports NASA's Vision for Space Exploration and is a member of the Coalition for Space Exploration and the...

  • John W. Campbell Memorial Award—1974—The Cosmic Connection: An Extraterrestrial Perspective
  • Joseph Priestley Award
    Joseph Priestley
    Joseph Priestley, FRS was an 18th-century English theologian, Dissenting clergyman, natural philosopher, chemist, educator, and political theorist who published over 150 works...

    —"For distinguished contributions to the welfare of mankind"
  • Klumpke-Roberts Award
    Klumpke-Roberts Award
    The Klumpke-Roberts Award was established from a bequest by astronomer Dorothea Klumpke-Roberts and recognizes outstanding contributions to the public understanding and appreciation of astronomy...

     of the Astronomical Society of the Pacific
    Astronomical Society of the Pacific
    The Astronomical Society of the Pacific is a scientific and educational organization, founded in San Francisco on February 7, 1889. Its name derives from its origins on the Pacific Coast, but today it has members all over the country and the world...

    —1974
  • Konstantin Tsiolkovsky
    Konstantin Tsiolkovsky
    Konstantin Eduardovich Tsiolkovsky was an Imperial Russian and Soviet rocket scientist and pioneer of the astronautic theory. Along with his followers the German Hermann Oberth and the American Robert H. Goddard, he is considered to be one of the founding fathers of rocketry and astronautics...

     Medal—Awarded by the Soviet Cosmonauts Federation
  • Locus Award
    Locus Award
    The Locus Award is a literary award established in 1971 and presented to winners of Locus magazine's annual readers' poll. Currently, the Locus Awards are presented at an annual banquet...

     1986—Contact
  • Lowell Thomas
    Lowell Thomas
    Lowell Jackson Thomas was an American writer, broadcaster, and traveler, best known as the man who made Lawrence of Arabia famous...

     Award—Explorers Club—75th Anniversary
  • Masursky Award
    Masursky Award
    The Harold Masursky Award for Meritorious Service to Planetary Science, usually called the Masursky Award, is awarded annually by the Division for Planetary Sciences of the American Astronomical Society...

    American Astronomical Society
    American Astronomical Society
    The American Astronomical Society is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC...

  • Miller Research Fellows
    Miller Research Fellows
    The Miller Fellow program is the central program of the Adolph C. and Mary Sprague Miller Institute for Basic Research in Science on the University of California Berkeley campus, which constitutes the support of Research Fellows - a group of the world’s most brilliant young scientists...

    hip—Miller Institute
    Miller Institute
    The Miller Institute for Basic Research in Science was established on the University of California, Berkeley campus in 1955 after Adolph C. Miller and his wife, Mary Sprague Miller made a donation to the University...

     (1960–1962)
  • Oersted Medal
    Oersted Medal
    The Oersted Medal recognizes notable contributions to the teaching of physics. Established in 1936, it is awarded by the American Association of Physics Teachers. The award is named for Hans Christian Ørsted. It is the Association's most prestigious award....

    —1990—American Association of Physics Teachers
    American Association of Physics Teachers
    The American Association of Physics Teachers was founded in 1930 for the purpose of "dissemination of knowledge of physics, particularly by way of teaching." There are more than 10,000 members that reside in over 30 countries. AAPT publications include two peer-reviewed journals, the American...

  • Peabody Award
    Peabody Award
    The George Foster Peabody Awards recognize distinguished and meritorious public service by radio and television stations, networks, producing organizations and individuals. In 1939, the National Association of Broadcasters formed a committee to recognize outstanding achievement in radio broadcasting...

    —1980—PBS series Cosmos
  • Prix Galbert—The international prize of Astronautics
    Astronautics
    Astronautics, and related astronautical engineering, is the theory and practice of navigation beyond the Earth's atmosphere. In other words, it is the science and technology of space flight....

  • Public Welfare Medal
    Public Welfare Medal
    The Public Welfare Medal is awarded by the U.S. National Academy of Sciences "in recognition of distinguished contributions in the application of science to the public welfare." It is the most prestigious honor conferred by the Academy...

    —1994—National Academy of Sciences
    United States National Academy of Sciences
    The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...

  • Pulitzer Prize for General Non-Fiction
    Pulitzer Prize
    The Pulitzer Prize is a U.S. award for achievements in newspaper and online journalism, literature and musical composition. It was established by American publisher Joseph Pulitzer and is administered by Columbia University in New York City...

    —1978—The Dragons of Eden
    The Dragons of Eden
    The Dragons of Eden: Speculations on the Evolution of Human Intelligence is a Pulitzer Prize winning 1977 book by Carl Sagan. In it, he combines the fields of anthropology, evolutionary biology, psychology, and computer science to give a perspective of how human intelligence evolved.One of the main...

  • SF Chronicle Award—1998—Contact
    Contact (novel)
    Contact is a science fiction novel written by Carl Sagan and published in 1985. It deals with the theme of contact between humanity and a more technologically advanced, extraterrestrial life form. It ranked No. 7 on the 1985 U.S. bestseller list....

  • Named the "99th Greatest American" on the June 5, 2005, Greatest American show on the Discovery Channel
    Discovery Channel
    Discovery Channel is an American satellite and cable specialty channel , founded by John Hendricks and distributed by Discovery Communications. It is a publicly traded company run by CEO David Zaslav...

  • Named an honorary member of the Demosthenian Literary Society
    Demosthenian Literary Society
    The Demosthenian Literary Society is a debating society at The University of Georgia in Athens, Georgia. It was founded in 1803 by the first graduating class of the University's Franklin College. The society was founded on February 19, 1803 and the anniversary is celebrated now with the Society's...

     on November 10, 2011
  • 2009 New Jersey Hall of Fame
    New Jersey Hall of Fame
    The New Jersey Hall of Fame is an organization that honors individuals from the U.S. state of New Jersey who have made contributions to society and the world beyond....

     inductee.

Publications

  • Planets (LIFE Science Library
    Life Science Library
    The Life Science Library was a popular series of hardbound books published by Time-Life between 1963 and 1967. Each of the 26 volumes explored a major topic of the natural sciences. They were intended for, and written at a level appropriate to, an educated lay readership...

    ), Sagan, Carl, Jonathan Norton Leonard and editors of Life, Time, Inc., 1966
  • Intelligent Life in the Universe
    Intelligent life in the Universe
    About intelligent life in the Universe, see:* Life on Earth* Extraterrestrial life#Evolution and morphology* Intelligent Life in the Universe...

    , I.S. Shklovskii coauthor, Random House, 1966, ISBN 1-892803-02-X, 509 pgs (note: republished in 1998 by Emerson-Adams Press)
  • UFOs: A Scientific Debate, Thornton Page coauthor, Cornell University Press, 1972, 310 pgs
  • Communication with Extraterrestrial Intelligence
    Communication with Extraterrestrial Intelligence
    Communication with extraterrestrial intelligence is a branch of the search for extraterrestrial intelligence that focuses on composing and deciphering messages that could theoretically be understood by another technological civilization. The best-known CETI experiment was the 1974 Arecibo message...

    . MIT Press, 1973, 428 pgs
  • Mars and the Mind of Man, Sagan, Carl, et al., Harper & Row, 1973, 143 pgs
  • The Cosmic Connection: An Extraterrestrial Perspective, Jerome Agel coauthor, Anchor Press, 1973, ISBN 0-521-78303-8, 301 pgs
  • Other Worlds
    Other Worlds
    Other Worlds EP is Screaming Trees' 1985 debut, produced by Steve Fisk. It was released on Velvetone Records and distributed by K Records...

    . Bantam Books, 1975
  • Murmurs of Earth: The Voyager Interstellar Record, Sagan, Carl, et al., Random House, ISBN 0-394-41047-5, 1978
  • The Dragons of Eden: Speculations on the Evolution of Human Intelligence
    The Dragons of Eden
    The Dragons of Eden: Speculations on the Evolution of Human Intelligence is a Pulitzer Prize winning 1977 book by Carl Sagan. In it, he combines the fields of anthropology, evolutionary biology, psychology, and computer science to give a perspective of how human intelligence evolved.One of the main...

    . Ballantine Books, 1978, ISBN 0-345-34629-7, 288 pgs
  • Broca's Brain: Reflections on the Romance of Science
    Broca's Brain: Reflections on the Romance of Science
    Broca's Brain: Reflections on the Romance of Science is a 1979 book by astrophysicist Carl Sagan. Its chapters were originally articles published between 1974 and 1979 in various magazines, including Atlantic Monthly, New Republic, Physics Today, Playboy and Scientific American...

    . Ballantine Books, 1979, ISBN 0-345-33689-5, 416 pgs
  • Cosmos
    Cosmos (book)
    Cosmos is a popular science book by astronomer and Pulitzer Prize-winning author Carl Sagan. Its 13 illustrated chapters, corresponding to the 13 episodes of the Cosmos TV series on which the book was based, explore the mutual development of science and civilization...

    . Random House, 1980. Random House New Edition, May 7, 2002, ISBN 0-375-50832-5, 384 pgs
  • The Cold and the Dark: The World after Nuclear War
    The Cold and the Dark: The World after Nuclear War
    The Cold and the Dark: The World after Nuclear War is a 1984 non-fiction book by Paul R. Ehrlich, Carl Sagan and Donald Kennedy. It makes dramatic predictions of the effect of nuclear conflagration on the earth's climate ....

    , Sagan, Carl et al., Sidgwick & Jackson, 1985
  • Comet
    Comet (book)
    Comet is a popular-science book by Carl Sagan and Ann Druyan. It describes the scientific nature of comets, as well as their varying roles and perceptions throughout history...

    , Ann Druyan
    Ann Druyan
    Ann Druyan is an American author and producer specializing in productions about cosmology and popular science. She made substantial contributions to the PBS documentary series, Cosmos, and was the wife of late scientist and educator, Carl Sagan.-Film career:Along with Carl Sagan and Steven Soter,...

     coauthor, Ballantine Books, 1985, ISBN 0-345-41222-2, 496 pgs
  • Contact
    Contact (novel)
    Contact is a science fiction novel written by Carl Sagan and published in 1985. It deals with the theme of contact between humanity and a more technologically advanced, extraterrestrial life form. It ranked No. 7 on the 1985 U.S. bestseller list....

    . Simon and Schuster, 1985; Reissued August 1997 by Doubleday Books, ISBN 1-56865-424-3, 352 pgs
  • A Path Where No Man Thought: Nuclear Winter and the End of the Arms Race, Richard Turco coauthor, Random House, 1990, ISBN 0-394-58307-8, 499 pgs
  • Shadows of Forgotten Ancestors: A Search for Who We Are, Ann Druyan
    Ann Druyan
    Ann Druyan is an American author and producer specializing in productions about cosmology and popular science. She made substantial contributions to the PBS documentary series, Cosmos, and was the wife of late scientist and educator, Carl Sagan.-Film career:Along with Carl Sagan and Steven Soter,...

     coauthor, Ballantine Books, October 1993, ISBN 0-345-38472-5, 528 pgs
  • Pale Blue Dot: A Vision of the Human Future in Space. Random House, November 1994, ISBN 0-679-43841-6, 429 pgs
  • The Demon-Haunted World: Science as a Candle in the Dark
    The Demon-Haunted World
    The Demon-Haunted World: Science as a Candle in the Dark is a book by astrophysicist Carl Sagan, which was first published in 1995.The book is intended to explain the scientific method to laypeople, and to encourage people to learn critical or skeptical thinking...

    . Ballantine Books, March 1996, ISBN 0-345-40946-9, 480 pgs (note: the book was first published and copyrighted in 1995 with an errata slip inserted)
  • Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium
    Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium
    Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium, published by Random House in 1997 , is the last book written by renowned American astronomer and science popularizer Carl Sagan before his death in 1996....

    , Ann Druyan
    Ann Druyan
    Ann Druyan is an American author and producer specializing in productions about cosmology and popular science. She made substantial contributions to the PBS documentary series, Cosmos, and was the wife of late scientist and educator, Carl Sagan.-Film career:Along with Carl Sagan and Steven Soter,...

     coauthor, Ballantine Books, June 1997, ISBN 0-345-37918-7, 320 pgs
  • The Varieties of Scientific Experience: A Personal View of the Search for God, Carl Sagan (writer) & Ann Druyan (editor), 1985 Gifford lectures
    Gifford Lectures
    The Gifford Lectures were established by the will of Adam Lord Gifford . They were established to "promote and diffuse the study of Natural Theology in the widest sense of the term — in other words, the knowledge of God." The term natural theology as used by Gifford means theology supported...

    , Penguin Press HC, November 2006, ISBN 1-59420-107-2, 304 pgs

External links